hdu 6208 The Dominator of Strings【AC自动机】

hdu 6208 The Dominator of Strings【AC自动机】

求一个串包含其他所有串，找出最长串去匹配即可，但是匹配时要对走过的结点标记，不然T死QAQ，，扎心了。。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
inline void read(int&a){char c;while(!(((c=getchar())>='0')&&(c<='9')));a=c-'0';while(((c=getchar())>='0')&&(c<='9'))(a*=10)+=c-'0';}
const int N = 100005;
const int M = 26;
struct Trie {
    int next[N][M], fail[N], tag[N];
    int root;
    int vis[N];
    int L;
    int newnode() {
        for(int i = 0;i < M;i++)
            next[L][i] = -1;
        vis[L] = 0;
        tag[L++] = 0;
        
        return L-1;
    }
    void init() {
        L = 0;
        root = newnode();
    }
    void Insert(char buf[]) {
        int len = strlen(buf);
        int u = root;
        for(int i = 0; i < len; i++) {
            if(next[u][buf[i]-'a'] == -1)
                next[u][buf[i]-'a'] = newnode();
            u = next[u][buf[i]-'a'];
        }
        tag[u]++;
    }
    void build() {
        queue<int> Q;
        fail[root] = root;
        for(int i = 0; i < M; i++) {
            if(next[root][i] == -1)
                next[root][i] = root;
            else {
                fail[next[root][i]] = root;
                Q.push(next[root][i]);
            }
        }
        while( !Q.empty() ) {
            int u = Q.front();
            Q.pop();
            for(int i = 0; i < M; i++) {
                int &v = next[u][i];
                if(v == -1)
                    v = next[fail[u]][i];
                else {
                    Q.push(v);
                    fail[v] = next[fail[u]][i];
                }
            }
        }
    }
    int query(char buf[]) {
        int len = strlen(buf);
        int u = root;
        int res = 0;
        for(int i = 0; i < len; i++) {
            u = next[u][buf[i]-'a'];
            int t = u;
            while( t != root && !vis[t] ) {
                res += tag[t];
                
                vis[t] = 1;//要不然会t啊
                
                tag[t] = 0;
                t = fail[t];
                
            }
        }
        return res;
    }
};
char s[N];
char ss[N];
Trie ac;
int main() {
    int t, n;
    read(t);
    while(t--){
        int ma = 0;
        ac.init();
        read(n);

        for(int i=0; i<n; i++){
            scanf("%s",s);
            int len = strlen(s);
            ac.Insert(s);
            if(ma <= len){
                ma = len; strcpy(ss, s);
            }
        }
        ac.build();
        int ans = ac.query(ss);
        if(ans == n){
            printf("%s
",ss);
        }
        else printf("No
");
    }
    return 0;
}